U.S. patent number 11,317,939 [Application Number 17/246,353] was granted by the patent office on 2022-05-03 for thrombectomy devices with maceration.
This patent grant is currently assigned to Vetex Medical Limited. The grantee listed for this patent is Vetex Medical Limited. Invention is credited to Mark Bruzzi, Paul Heneghan, Saeid Kasiri Ghahi.
United States Patent |
11,317,939 |
Bruzzi , et al. |
May 3, 2022 |
Thrombectomy devices with maceration
Abstract
A thrombectomy device includes a handle at a proximal end
portion of the device, a first arm connected to the handle, and a
second arm extending to a distal end portion of the device. The
device may also include a cage at the distal end portion of the
device, the cage being adjustable between a contracted orientation
and an expanded orientation, the cage including a cutting element
disposed between a proximal end portion of the cage and a distal
end of the cage, the cutting element including one or more of a
round wire, a flat wire, or a blade configured to remove matter
from a body lumen when the cage is in the expanded orientation, and
a macerator extending within the first arm and the second arm, the
macerator including a helical element.
Inventors: |
Bruzzi; Mark (Galway,
IE), Kasiri Ghahi; Saeid (Galway, IE),
Heneghan; Paul (Galway, IE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Vetex Medical Limited |
Galway |
N/A |
IE |
|
|
Assignee: |
Vetex Medical Limited (Galway,
IE)
|
Family
ID: |
1000006277622 |
Appl.
No.: |
17/246,353 |
Filed: |
April 30, 2021 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20210251651 A1 |
Aug 19, 2021 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
17133111 |
Dec 23, 2020 |
|
|
|
|
15936635 |
Dec 29, 2020 |
10874421 |
|
|
|
15008057 |
Sep 22, 2020 |
10779852 |
|
|
|
14776633 |
Oct 27, 2020 |
10813663 |
|
|
|
PCT/IE2014/000005 |
Mar 18, 2014 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Mar 15, 2013 [EP] |
|
|
13159640 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/32056 (20130101); A61B 17/320783 (20130101); A61B
17/221 (20130101); A61B 17/320725 (20130101); A61B
17/320758 (20130101); A61B 2017/320733 (20130101); A61B
2017/00685 (20130101); A61B 2017/320008 (20130101); A61B
2017/320064 (20130101); A61B 2017/2212 (20130101); A61B
2217/005 (20130101) |
Current International
Class: |
A61B
17/221 (20060101); A61B 17/3207 (20060101); A61B
17/3205 (20060101); A61B 17/00 (20060101); A61B
17/32 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0117519 |
|
Sep 1984 |
|
EP |
|
1 736 106 |
|
Dec 2006 |
|
EP |
|
1310219 |
|
Jan 2007 |
|
EP |
|
1310219 |
|
Mar 2007 |
|
EP |
|
2967614 |
|
Jan 2016 |
|
EP |
|
3202340 |
|
Aug 2017 |
|
EP |
|
3305220 |
|
Apr 2018 |
|
EP |
|
3305221 |
|
Apr 2018 |
|
EP |
|
3305221 |
|
Apr 2018 |
|
EP |
|
S 63212339 |
|
Sep 1988 |
|
JP |
|
H05137729 |
|
Jun 1993 |
|
JP |
|
H 8509639 |
|
Oct 1996 |
|
JP |
|
H11506358 |
|
Jun 1999 |
|
JP |
|
2000504263 |
|
Apr 2000 |
|
JP |
|
2003265488 |
|
Sep 2003 |
|
JP |
|
2003530903 |
|
Oct 2003 |
|
JP |
|
2004500171 |
|
Jan 2004 |
|
JP |
|
2005006779 |
|
Jan 2005 |
|
JP |
|
2006511266 |
|
Apr 2006 |
|
JP |
|
4330571 |
|
Nov 2006 |
|
JP |
|
2006305301 |
|
Nov 2006 |
|
JP |
|
2010532211 |
|
Oct 2010 |
|
JP |
|
2010532211 |
|
Oct 2010 |
|
JP |
|
2016513524 |
|
May 2016 |
|
JP |
|
2019022755 |
|
Feb 2019 |
|
JP |
|
2020195854 |
|
Dec 2020 |
|
JP |
|
2020195855 |
|
Dec 2020 |
|
JP |
|
WO 91/04763 |
|
Apr 1991 |
|
WO |
|
WO 97/17892 |
|
May 1997 |
|
WO |
|
WO 98/50103 |
|
Nov 1998 |
|
WO |
|
WO 01/08743 |
|
Feb 2001 |
|
WO |
|
WO 01/19444 |
|
Mar 2001 |
|
WO |
|
WO 01/39673 |
|
Jun 2001 |
|
WO |
|
WO 01/74255 |
|
Oct 2001 |
|
WO |
|
WO 01/87168 |
|
Nov 2001 |
|
WO |
|
WO 01/28618 |
|
Dec 2001 |
|
WO |
|
WO 02/11626 |
|
Aug 2002 |
|
WO |
|
WO 02/11627 |
|
Nov 2002 |
|
WO |
|
WO 03/018085 |
|
Mar 2003 |
|
WO |
|
WO 02/094111 |
|
Apr 2003 |
|
WO |
|
WO 02/094130 |
|
Oct 2003 |
|
WO |
|
WO 03/077799 |
|
Apr 2004 |
|
WO |
|
WO 05/046736 |
|
May 2005 |
|
WO |
|
WO 05/055878 |
|
Jun 2005 |
|
WO |
|
WO 05/112770 |
|
Dec 2005 |
|
WO |
|
WO 06/107641 |
|
Oct 2006 |
|
WO |
|
WO 06/110186 |
|
Oct 2006 |
|
WO |
|
WO 07/061418 |
|
May 2007 |
|
WO |
|
WO 08/097993 |
|
Aug 2008 |
|
WO |
|
WO 09/021071 |
|
Feb 2009 |
|
WO |
|
WO 09/067629 |
|
May 2009 |
|
WO |
|
WO 09/079539 |
|
Jun 2009 |
|
WO |
|
WO 09/086154 |
|
Jul 2009 |
|
WO |
|
WO 09/089297 |
|
Jul 2009 |
|
WO |
|
WO 09/105710 |
|
Aug 2009 |
|
WO |
|
WO 09/114046 |
|
Sep 2009 |
|
WO |
|
WO 09/124288 |
|
Oct 2009 |
|
WO |
|
WO 09/126935 |
|
Oct 2009 |
|
WO |
|
WO 09/154441 |
|
Dec 2009 |
|
WO |
|
WO 10/049121 |
|
May 2010 |
|
WO |
|
WO 10/082187 |
|
Jul 2010 |
|
WO |
|
WO 10/082188 |
|
Jul 2010 |
|
WO |
|
WO 11/021119 |
|
Feb 2011 |
|
WO |
|
WO 11/079111 |
|
Jun 2011 |
|
WO |
|
WO 11/151910 |
|
Dec 2011 |
|
WO |
|
WO 2011/151911 |
|
Dec 2011 |
|
WO |
|
WO 12/156069 |
|
Nov 2012 |
|
WO |
|
WO 13/109756 |
|
Jul 2013 |
|
WO |
|
WO 14/004244 |
|
Jan 2014 |
|
WO |
|
WO 14/055609 |
|
Apr 2014 |
|
WO |
|
WO 14/070405 |
|
May 2014 |
|
WO |
|
WO 14/074318 |
|
May 2014 |
|
WO |
|
WO 14/085590 |
|
Jun 2014 |
|
WO |
|
WO 14/127389 |
|
Aug 2014 |
|
WO |
|
WO 14/127738 |
|
Aug 2014 |
|
WO |
|
WO 14/141226 |
|
Sep 2014 |
|
WO |
|
WO 14/150013 |
|
Sep 2014 |
|
WO |
|
WO 14/154137 |
|
Oct 2014 |
|
WO |
|
WO 15/057796 |
|
Apr 2015 |
|
WO |
|
Other References
International Search Report and Written Opinion of International
Application No. PCT/IE2014/000005, dated Jul. 7, 2014, (15 pages).
cited by applicant .
International Search Report and Written Opinion in pending
International Application No. PCT/EP2015/075995 dated Apr. 21, 2016
(16 pages). cited by applicant .
European Search Report for European Application No. 16201115.9,
dated Jun. 14, 2017 (8 pages). cited by applicant .
"U.S. Appl. No. 15/008,057, Non Final Office Action dated May 9,
2016", 20 pgs. cited by applicant .
"U.S. Appl. No. 15/008,057, Notice of Allowance dated May 11,
2020", 8 pgs. cited by applicant .
"U.S. Appl. No. 15/936,635, Preliminary Amendment filed Mar. 27,
2018", 9 pgs. cited by applicant .
"U.S. Appl. No. 17/133,111, Preliminary Amendment filed Apr. 17,
2021", 9 pgs. cited by applicant .
"U.S. Appl. No. 17/246,120, Preliminary Amendment filed Jun. 25,
2021", 9 pgs. cited by applicant .
"European Application Serial No. 17198610.2, Response filed Oct. 7,
2021 to Communication Pursuant to Article 94(3) EPC dated Jun. 8,
2021", 45 pgs. cited by applicant .
"Japanese Application Serial No. 2020-151485, Notification of
Reasons for Refusal dated Sep. 14, 2021", with English translation,
6 pages. cited by applicant .
"U.S. Appl. No. 17/246,120, Supplemental Notice of Allowability
dated Feb. 2, 2022", 3 pgs. cited by applicant .
"U.S. Appl. No. 17/246,120, Response filed Oct. 26, 2021 to Non
Final Office Action dated Jul. 26, 2021", 10 pages. cited by
applicant .
"U.S. Appl. No. 17/246,120, Notice of Allowance dated Nov. 9,
2021", 8 pages. cited by applicant .
"U.S. Appl. No. 17/133,111, Final Office Action dated Nov. 16,
2021", 21 pages. cited by applicant .
"Japanese Application Serial No. 2020-151485, Response filed Dec.
13, 2021 to Notification of Reasons for Refusal dated Sep. 14,
2021", with English claims, 7 pages. cited by applicant .
"Japanese Application Serial No. 2020-151484, Notification of
Reasons for Refusal dated Jan. 4, 2022", with English translation,
6 pages. cited by applicant .
"Japanese Application Serial No. 2020-151484, Response filed Dec.
13, 2021 to Notification of Reasons for Refusal dated Sep. 14,
2021", with English claims, 6 pages. cited by applicant.
|
Primary Examiner: Miles; Wade
Attorney, Agent or Firm: Schwegman Lundberg & Woessner,
P.A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No.
17/133,111, filed Dec. 23, 2020, which is a continuation of U.S.
application Ser. No. 15/936,635, filed Mar. 27, 2018, which is a
continuation of U.S. application Ser. No. 15/008,057, filed Jan.
27, 2016, which is a continuation of U.S. application Ser. No.
14/776,633, filed Sep. 14, 2015, which is the U.S. national phase
entry under 35 U.S.C. .sctn. 371 of PCT Application No.
PCT/IE2014/000005, filed on Mar. 18, 2014, which claims priority to
European Application No. 13159640.5, filed on Mar. 15, 2013, the
entireties of each of which are incorporated by reference herein.
Claims
The invention claimed is:
1. An extraction device, comprising: a handle at a proximal end
portion of the device; a tubular first arm having a window
extending radially within a side wall of the first tubular arm; a
second arm extending to a distal end portion of the device; a cage
at the distal end portion of the device, the cage being adjustable
between a contracted orientation and an expanded orientation, the
cage including a cutting element disposed between a proximal end
portion of the cage and a distal end of the cage, the cutting
element including one or more of a round wire, a flat wire, or a
blade configured to remove matter from a body lumen when the cage
is in the expanded orientation; a macerator extending within the
first arm and around the second arm, the macerator including a
helical element at least partially exposed through the window; and
wherein the cage surrounds a portion of the first arm including the
window.
2. The device of claim 1, wherein the helical element surrounds a
third arm.
3. The device of claim 2, wherein the third arm is configured to
rotate with respect to the first arm and the second arm.
4. The device of claim 1, wherein the macerator includes a cutting
edge.
5. The device of claim 1, wherein a pitch of the helical element
changes along a length of the macerator.
6. The device of claim 1, wherein the second arm includes a filter
configured to allow fluid to exit the macerator.
7. An extraction device, comprising: a proximal end portion; a
distal end portion; a proximal tube having a side wall with a
window extending through the side wall from an interior of the
proximal tube to an exterior of the proximal tube; a
radially-expandable cage connected to the proximal tube and
extending to the distal end portion, the cage including struts
forming a plurality of proximal openings and a plurality of distal
openings, at least one of the proximal openings being larger than
at least one of the distal openings; a cutting element including
one or more of a round wire, a flat wire, or a blade disposed at a
widest portion of the cage, the cutting element being configured to
remove matter from a body lumen by applying a shearing force; and a
maceration device having a surface for removing matter scraped from
the body lumen by the cutting element, the maceration device being
rotatable with respect to the cage and the proximal tube and in
communication with the exterior of the proximal tube through the
window within the radially-expandable cage.
8. The device of claim 7, further including a sheath surrounding at
least a portion of the proximal tube.
9. The device of claim 7, wherein the maceration device includes a
cutting edge on a helical formation of the maceration device.
10. The device of claim 7, further including a distal tube, wherein
the maceration device includes a portion that extends within the
distal tube.
11. The device of claim 7, wherein the maceration device includes a
helical formation extending within the proximal tube.
12. An extraction device, comprising: a proximal end portion; a
distal end portion; a proximal tube having a window extending
radially from an interior to an exterior of the proximal tube; a
radially-expandable cage connected to the proximal tube and
extending to the distal end portion, the cage including struts
forming a plurality of proximal openings and a plurality of distal
openings, at least one of the proximal openings being larger than
at least one of the distal openings; a scraping element disposed at
the cage, the scraping element being configured to remove matter
from a body lumen when the cage is in an expanded orientation; and
a maceration device for removing matter removed from the body
lumen, the maceration device rotatable with respect to the cage and
the proximal tube, and the macerator at least partially exposed
through the window and in communication with the exterior of the
proximal tube within the radially-expandable cage.
13. The device of claim 12, wherein the proximal openings are
defined by a plurality of wires that form the struts.
14. The device of claim 13, wherein the wires that define the
proximal openings are twisted together, forming twisted wires.
15. The device of claim 14, wherein the twisted wires include first
portions that define the proximal openings and second portions that
define the distal openings, the second portions being less tightly
twisted as compared to the first portions, and the scraping element
is formed at an intersection of the first and second portions.
16. The device of claim 13, wherein a helical formation of the
maceration device extends beyond a distal end of the proximal
tube.
17. The device of claim 16, wherein the maceration device includes
a tube that extends distally of the helical formation.
18. The device of claim 17, wherein a pitch of the helical
formation changes over a length of the maceration device.
Description
TECHNICAL FIELD
The invention relates to a device suitable for removing matter from
inside the lumen and the wall of a body lumen. In particular, the
invention relates to a thrombectomy device for removing thrombus
from the walls of a vein or artery of a human.
BACKGROUND TO THE INVENTION
There have been many methods and devices to extract a blockage from
vessels. Thrombectomy devices exist that macerate and extract the
clot rather than pulling out the clot intact. The followings are
some of the related patents.
U.S. Pat. No. 5,972,019 introduces an embolism treatment device
having a core element and a cage. The cage may include an
expandable braid which is rotatably attached to the core element
and can be opened to separate the clot from the vessel wall or be
expanded beyond the clot to pull it out. The core element has a
rotatable part which is non removable from the cage.
U.S. Pat. No. 6,066,158 discloses an embolectomy device having a
core wire element and a spiral collector to collect the embolism.
The device may also have an actuator to allow expansion of the cage
after delivery.
U.S. Pat. No. 5,795,322 presents a device for reducing the size of
thrombus and removing it from the vessel. The device is a tube-like
catheter with a filter formed from longitudinal strip-shape of the
catheter. The filter opens when the distal and the proximal sided
are pushed towards each other respectively. The device comprises a
jet flow and lumen to extract the clot.
U.S. Pat. No. 6,660,014 presents a catheter for removing occlusive
material from vessel lumen. The catheter comprises a radially
expandable positioning cage and a radially expandable macerator
within the cage. The diameter of the cage is adjustable with
predetermined unconstrained diameter. U.S. Pat. No. 6,454,775
discloses an expansible macerator.
Patent application US 2006/0229645 presents a radially expansible
cage for the removal of hardened and aged thrombus from the vessel
wall. The cage opening and closing is controlled at the
proximal/user end by moving the cage ends closer together or
further apart; this is done either manually, or with a threaded
tube to define the radial expansion of the cage.
U.S. Pat. No. 6,383,205 presents a mechanism including a double
filter device to extract the clot with minimum risk of
embolism.
U.S. Pat. No. 6,616,679 is a vascular device for emboli and
thrombus removal. It includes a blood permeable sac which collects
the emboli and can be collapsed. This is a fast way to extract
small emboli but for large clot the sac need to be extremely
long.
In U.S. Pat. No. 6,652,548 a thrombectomy device has been claimed.
The catheter based device comprises shearing members located at the
distal ends of the catheter and the inner shearing member is
rotatable.
U.S. Pat. Nos. 6,656,203, 7,083,633, 7,014,647, 6,558,405,
EP1310219A3, EP1310219B1, 20070173883, U.S. Pat. Nos. 6,179,859,
7,922,741 and US20110125181 are examples of different structures
for embolic filters. The filter may be placed in the vessel prior
to an operation such as stenting or PTCA. After the operation, the
filter is collapsed and taken out of the body. Neither of the
filters are suitable for large tapered veins with thrombosis.
Because filters are not designed to be moved along vessels after
deployment, this makes it difficult to remove long thrombus. The
existing devices and methods described above do not have a high
performance in harvesting large volumes of thrombus and also
thrombus in large and/or tapered and/or branched vessels.
Limitations associated with these devices include procedural
duration and thrombus removal efficiency.
It is an object of the invention to overcome at least one of the
above-referenced problems.
STATEMENTS OF INVENTION
Broadly, the invention provides a device suitable for use in a body
lumen comprising an elongated control member and a radially
expansible member (i.e. a cage, funnel, or a ring) disposed at or
adjacent to a distal end of the elongated control arm and that is
adjustable between a contracted orientation and an expanded
(deployed) orientation. The radially expansible member is adapted
to remove matter (i.e. thrombus) from the walls of a body lumen
(i.e. veins, arteries or other lumens such as the urethra), for
example scrape thrombus from vessel walls, collect matter removed
from the walls of a lumen, and optionally both, when in a deployed
orientation. The control member comprises two arms, one of which is
connected to or adjacent to a proximal end of the radially
expansible member and the other of which is connected to or
adjacent to a distal end of the radially expansible member.
Movement of one of the arms relative to the other effects
adjustment of the diameter or radial strength of the radially
expansible member, for example adjustment of the diameter from a
contracted orientation to an expanded (deployed) orientation, or
adjustment of the radial force from a first force to a greater
force. The movement is preferably longitudinal movement. The device
additionally includes a control mechanism that is ideally
operatively connected to both arms and provides resistance to
movement of one of the arms relative to the other. The control
mechanism may comprise biasing means for biasing the radially
expansible member into, or in the direction of, an expanded or
contracted orientation (FIG. 11), it may include brake means which
clamp the two arms in one orientation with a certain force such
that movement of one of the arms relative to the other only occurs
when a specific predetermined force is applied to the radially
expansible member (FIG. 9), or it may comprise a combination of
biasing means and brake means (FIG. 12).
A device of the invention is ideally suited for use in tapering
lumens with obstructions such as valves where movement of the cage
in a deployed shape along the lumen requires the diameter of the
cage to change. When the lumen is tapering inwardly (in the
direction of travel of the cage), the control mechanism exerts a
force on the radially expansible member resisting contraction of
the radially expansible member (by biasing the radially expansible
member into an expanded orientation or by clamping the two arms in
a specific disposition) until the force exerted on the radially
expansible member by the lumen exceeds the total resistance force
including that exerted by the resistance mechanism at which point
the diameter of the radially expansible member will reduce. This
means that the radially expansible member can be moved along the
walls of the lumen exerting radial force against the walls, thereby
effecting a scraping/collecting action.
Likewise, when the tube is tapering outwardly (in the direction of
travel of the cage), the resistance mechanism comprises biasing
means that exerts a force on the cage by biasing the cage into an
expanded orientation. This means that cage will scrape along the
walls of the vasculature exerting radial force against the walls,
thereby effecting a scraping action along the outwardly tapering
walls.
According to the invention, there is provided a device suitable for
use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a radially expansible
member disposed at or near the distal end and adapted for
collection and/or shearing of matter from a wall of the body lumen,
the radially expansible member having a proximal end and a distal
end and being adjustable between a contracted orientation and an
expanded orientation, the elongated control member comprising a
proximal arm connected to the radially expansible member and a
distal arm connected to the radially expansible member distally of
the proximal arm connection such that movement of one arm relative
to the other arm effects adjustment of the diameter and/or radial
strength of the radially expansible member, the device being
characterised in that it comprises a control mechanism operatively
connected to both arms and adapted to provide resistance to the
movement of one arm relative to the other.
The distal arm is generally connected to the radially expansible
member distally of the proximal arm connection. Thus, the distal
arm may be connected at or adjacent to the distal end of the
radially expansible member, and the proximal arm may be connected
to the radially expansible member at a point between the distal arm
connection and the proximal end of the cage.
Preferably, the radially expansible member is a cage, although
other radially expansible members such as, for example, expansible
rings, funnels are envisaged. The radially expansible member may be
formed from one, two, or more struts, which may be arranged in a
helical arrangement to form the cage.
The distal or proximal arm may be, for example, a wire or a tube.
In one embodiment, one of the arms is a tube (for example the
proximal arm) and the other arm (for example the distal arm) is a
wire, in which the wire is suitably disposed within a lumen in the
tube. Suitably, the distal and proximal arms are co-extensive along
most of their length (for example they are coextensive up to the
cage). The control member comprising the two arms may be disposed
within a tube, typically a catheter tube. In a preferred
embodiment, the proximal arm is tubular and the distal arm is
disposed within the proximal arm. Preferably, the distal arm is
tubular (so as to facilitate the device being delivered over a
guidewire).
Typically, the control mechanism comprises biasing means adapted to
bias the radially expansible member into, or in the direction of,
the expanded or contacted orientation. Ideally, the control
mechanism comprises biasing means adapted to bias the cage into, or
in the direction of, the expanded orientation.
Suitably, the control mechanism comprises brake means adapted to
resist movement of one arm relative to the other arm. One
embodiment of a brake means is a friction screw, typically an
adjustable friction screw. Preferably, the control mechanism is
adjustable so that the level of resistance to movement can be
adjusted.
In one embodiment, the control mechanism comprises biasing means
adapted to bias the radially expansible member into, or in the
direction of, the expanded or contacted orientation and brake means
adapted to resist movement of one arm relative to the other arm,
for example brake means adapted to prevent expansion or retraction
of the radially expansible member.
Suitably, the control mechanism comprises a first part connected to
one of the arms, a second part connected to the other of the arms
and movable relative to the first part, and force controlled
resistance means for resisting movement of the first part relative
to the second part. The force controlled resistance means may be
biasing means adapted to bias the cage into, or in the direction
of, the expanded or contacted orientation, and/or brake means
adapted to resist movement of the radially expansible member or
movement or one arm relative to the other arm, typically both.
In this specification, the term "force controlled" as applied to
the resistance mechanism should be understood to mean that the
diameter of the radially expansible member is not predetermined or
controlled, but is dependent on the force applied.
In one preferred embodiment, the invention provides a device
suitable for use in a body lumen and comprising: an elongated
control member having a distal and a proximal end, and a radially
expansible member disposed at or near the distal end and adapted
for collection and/or shearing of matter from a wall of the body
lumen, the radially expansible member having a proximal end and a
distal end and being adjustable between a contracted orientation
and an expanded orientation, the elongated control member
comprising a proximal arm connected to the radially expansible
member and a tubular distal arm connected to the radially
expansible member distally of the proximal arm connection such that
movement of one arm relative to the other arm effects adjustment of
the diameter and/or radial strength of the radially expansible
member, a control mechanism operatively connected to both arms and
adapted to provide resistance to the movement of one arm relative
to the other, in which the control mechanism comprises a first part
connected to one of the arms, a second part connected to the other
of the arms that is movable relative to the first part, and force
controlled resistance means for resisting movement of the first
part relative to the second part, characterised in that the force
controlled resistance means comprises (a) biasing means for biasing
the radially expansible member into the expanded orientation, or
(b) a brake means adapted to resist movement of one of the first
and second parts relative to the other of the first and second
parts.
In another embodiment, the invention provides a device suitable for
use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a radially expansible
member disposed at or near the distal end and adapted for
collection and/or shearing of matter from a wall of the body lumen,
the radially expansible member having a proximal end and a distal
end and being adjustable between a contracted orientation and an
expanded orientation, a thrombus extractor, at least a part of
which is preferably disposed within the radially expansible member
the elongated control member comprising a proximal arm connected to
the radially expansible member and a distal arm connected to the
radially expansible member distally of the proximal arm connection
such that movement of one arm relative to the other arm effects
adjustment of the diameter and/or radial strength of the radially
expansible member, a control mechanism operatively connected to
both arms and adapted to provide resistance to the movement of one
arm relative to the other, in which the control mechanism comprises
a first part connected to one of the arms, a second part connected
to the other of the arms that is movable relative to the fixed
first part, and force controlled resistance means for resisting
movement of the first part relative to the second part,
characterised in that the force controlled resistance means
comprises (a) biasing means for biasing the radially expansible
member into the expanded orientation, or (b) a brake means adapted
to resist movement of one of the first and second parts relative to
the other of the first and second parts.
Typically, the force controlled resistance means comprises biasing
means, for example a resiliently deformable or displaceable member
such as for example a spring or a pneumatic or hydraulic member,
generally disposed between the first and second parts of the
control mechanism. The spring may be any type of spring, for
example a compression, tension, flat, constant force, or adjustable
constant spring.
In one embodiment, the force controlled resistance means comprises
biasing means, for example a resiliently deformable member disposed
between the first and second parts of the resistance mechanism, and
a brake means adapted or configured to resist movement of one of
the first and second parts relative to the other of the first and
second parts.
The control mechanism may be disposed at any point along the
device, for example proximal to the radially expansible member,
distal to the radially expansible member, or adjacent to or within
the radially expansible member. In a preferred embodiment, the
control mechanism is disposed at a proximal end of the catheter
(for example, on the handle) such that, in use, it is exposed proud
of the body.
In a preferred embodiment of the invention, the first part of the
control mechanism is connected to the proximal end of the radially
expansible member by means of the proximal arm, and the adjustable
second part of the control mechanism is attached to the distal end
of the radially expansible member by means of the distal arm. Thus,
the distal arm typically passes through the cage.
Preferably, the proximal arm is a tube comprising a lumen and the
distal arm is disposed within the lumen of the first arm, typically
coaxially with the first arm. Preferably, the distal arm is a tube,
ideally adapted for receipt of a guidewire.
Movement of one arm relative to the other arm effects adjustment of
the diameter and/or radial strength of the radially expansible
member. Preferably, the movement is longitudinal movement, although
other movement is envisaged, for example lateral, radial,
circumferential rotational or combinations thereof.
In one embodiment, the brake means comprises a friction screw fixed
to one of the parts of the control means and adjustable to engage
the other part of the control means (or the arm that is operably
connected to the other part). Preferably, the friction screw is
fixed to the second part, for example a movable stop forming part
of the second part, and is adjustable to engage the first part or
the control means or the distal arm that is operable connected to
the first part.
In one embodiment of the control mechanism, the first part
comprises a barrel, and the second part is adapted for sliding
movement within the barrel, wherein the resistance means comprises
a friction screw, preferably an adjustable friction screw, disposed
on the barrel and adapted for engagement with the second part.
Suitably, the resistance means additionally comprises biasing means
suitably adapted to bias the cage into, or in the direction of, the
expanded orientation.
Typically, the control mechanism is disposed proximally of the
radially expansible member such that in use it is located outside
of the body. Suitably, the first part is operably connected to the
proximal arm and comprises a guide path, and the second part is
operably connected to the distal arm and is associated with the
first part for movement along the guide path, and wherein the force
controlled resistance means comprises a resiliently deformable
member disposed along the guide path between the first and second
parts. Preferably, the first part comprises a barrel and a second
part comprises a block configured for sliding and controlled
movement within the barrel.
Typically, the first part comprises a movable stop which is movable
to vary the length of the guide path and/or the resiliently
deformable member.
Suitably, the brake means comprises a friction screw operably
connected to the movable stop and configured for adjustable
engagement with the distal arm.
Suitably, the control mechanism is disposed within the radially
expansible member and comprises a first part connected to the
distal arm, a second part connected to the proximal arm, and a
helical spring operatively connected to the first and second parts
and configured to provide force controlled resistance to movement
of the first and second parts together.
Preferably, the radially expansible member comprises a cage.
Suitably, the cage comprises a proximal portion having apertures
for receipt of thrombus into the cage, and a distal portion having
a fine mesh for capturing thrombus, in which the cage optionally
comprises a cut tube. Alternatively, the cage comprises a distal
portion having apertures for receipt of thrombus into the cage, and
a proximal portion having a fine mesh for capturing thrombus, in
which the cage optionally comprises a cut tube.
Suitably, the control mechanism is disposed distally of the
radially expansible member. Suitably, the control mechanism
comprises a resiliently deformable member (i.e a spring) having a
distal end (first part) operably connected to the distal arm and a
proximal end (second part) operably connected to a distal end of
the radially expansible member, and wherein the distal end of the
distal arm is operably connected to the distal end of the radially
expansible member by means of the resiliently deformable
member.
Preferably, the device comprises an extractor at least a part of
which is disposed within the radially expansible member. Suitably,
the extractor comprises holes or apertures dimensioned to allow
blood, but prevent thrombus, pass out of the extractor.
Suitably, the extractor comprises a helical formation adapted to
rotate. The rotation is adapted to remove thrombus from the
radially expansible member or optionally deliver agents into the
body lumen, for example a thrombolytic agent. The helical formation
may comprises a single, double or triple helical formation.
Typically, the pitch of the helix on the helical formation is
configured to squeeze blood from thrombus during use.
Typically, the helical formation is disposed within an extractor
tube. Ideally, a portion of the helical formation within the
radially expansible member is exposed by means of, for example, one
or more windows or cut-away portions.
Suitably, a leading edge of the extractor tube comprises a cutting
edge. Preferably, the helical formation comprises a cutting edge,
ideally disposed at or adjacent a distal end of the helical
formation. In one embodiment, a leading edge of the extractor tube
comprises a cutting edge and the extractor comprises an aspirator
tube.
In one embodiment, the thrombus extractor is an aspirator tube.
Typically, the force controlled resistance means is self-adjusting.
In this specification, the term "self adjusting" as applied to the
force controlled resistance means should be understood to mean that
the resistance means adjusts itself without any user input other
than the actions of the user to move the device along a vessel.
Typically, the elongated control member is contained within a
tubular sheath. Ideally the tubular sheath extends along all or
most of the length of the control member. Suitably, the
longitudinal position of the sheath is adjustable. Suitably, the
tubular sheath can be adjusted to cover the radially expansible
member and maintain the radially expansible member in a contracted
orientation.
Typically, the tubular sheath comprises a plurality of holes for
perfusion of a liquid.
Suitably, the device comprises a liquid administration lumen
configured to deliver a liquid into the body. Preferably, the
liquid administration lumen comprises a lumen formed within the
distal arm, between the distal arm and proximal arm, and between
the proximal arm and an external sheath. Ideally, the device
comprises an injection port for delivery of liquid into the liquid
administration lumen.
In a preferred embodiment, the invention provides a device suitable
for use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a radially expansible
member disposed at or near the distal end and adapted for
collection and/or shearing of matter from a wall of the body lumen,
the radially expansible member having a proximal end and a distal
end and being adjustable between a contracted orientation and an
expanded orientation, the elongated control member comprising a
proximal arm connected to the radially expansible member and a
distal arm connected to the radially expansible member distally of
the proximal arm connection such that movement of one arm relative
to the other arm effects adjustment of the diameter or radial
strength of the radially expansible member, the device being
characterised in that it comprises biasing means for biasing the
radially expansible member into, or in the direction of, an
expanded orientation.
In another embodiment, the invention provides a device suitable for
use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a radially expansible
member disposed at or near the distal end and adapted for
collection and/or shearing of matter from a wall of the body lumen,
the radially expansible member having a proximal end and a distal
end and being adjustable between a contracted orientation and an
expanded orientation, the elongated control member comprising a
proximal arm connected to the radially expansible member and a
distal arm connected to the radially expansible member distally of
the proximal arm connection such that movement of one arm relative
to the other arm effects adjustment of the diameter or radial
strength of the radially expansible member, the device being
characterised in that it comprises biasing means for biasing the
radially expansible member into, or in the direction of, an
expanded orientation and brake means brake means adapted to resist
movement of one arm relative to the other arm.
In another embodiment, the invention provides a device suitable for
use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a radially expansible
member disposed at or near the distal end and adapted for
collection and/or shearing of matter from a wall of the body lumen,
the radially expansible member having a proximal end and a distal
end and being adjustable between a contracted orientation and an
expanded orientation, the elongated control member comprising a
proximal arm connected to the radially expansible member and a
distal arm connected to the radially expansible member distally of
the proximal arm connection such that movement of one arm relative
to the other arm effects adjustment of the diameter or radial
strength of the radially expansible member, the device being
characterised in that it comprises a resistance mechanism
comprising a fixed first part connected to one of the arms, a
second part connected to the other of the arms and movable relative
to the fixed first part, and resistance means for resisting
movement of the first part relative to the second part, in which
the resistance means optionally comprises biasing means adapted to
bias the cage into the expanded or contacted orientation or brake
means adapted to prevent expansion of the cage.
In one embodiment, the radially expansible member is a cage.
Typically, the cage is a filtering cage (i.e. it is adapted to
collect or filter thrombus from blood that passes through the
cage). In another embodiment, the cage is a shearing cage (i.e. a
cage adapted to shear or scrape thrombus from a wall of the
vasculature). In a preferred embodiment, the cage is both a
shearing and filtering cage. Suitably, the cage has a proximal end
that is at least partially open (for receipt of thrombus). The cage
may comprise a braided material, for example a braided wire, or it
may comprise a cut tube, for example a cut tube (i.e. Polymeric,
metal such as stainless steel Nitinol or cobalt chromium, or
ceramic; or a combination of these materials) or a laser cut tube,
or it may comprise a braided material and a cut tube. When formed
from a braided material, the density of the braid may be greater
towards the distal end of the cage that the proximal end of the
cage. In a preferred embodiment, the cage is formed from a shape
memory material such as Nitinol. Preferably, the cage has an at
least partially open proximal end and tapers inwardly towards its
distal end.
In one embodiment, the cage comprises a distal section having a
fine mesh, and an intermediate section having large apertures.
Thus, the fine mesh is suited for filtering/capturing thrombus, and
the large apertures adapted for allowing passage into the cage of
thrombus. Typically, the cage is cut from a tube, suitably a
polymeric or metal tube.
In one embodiment, the cage comprises a cutting element disposed
circumferentially around the cage. This may be a wire, or a cutting
edge. Typically, at least a part of the cutting element is exposed
proud of the cage. Suitably, at least a part of the cutting element
is disposed within the cage. Typically, the cutting element is
disposed with respect to the cage such that the cutting element
expands and contracts with the expansion and contraction of the
cage, respectively.
In one embodiment, the invention provides a device suitable for use
in a body lumen and comprising: an elongated control member having
a distal and a proximal end, and a cage disposed at or near the
distal end and adapted for collection and/or shearing of matter
from a wall of the body lumen, the radially expansible member
having a proximal end and a distal end and being adjustable between
a contracted orientation and an expanded orientation, the elongated
control member comprising a proximal arm connected to the radially
expansible member and a distal arm connected to the radially
expansible member distally of the proximal arm connection such that
movement of one arm relative to the other arm effects adjustment of
the diameter or radial strength of the radially expansible member
the device being characterised in that the cage comprises a distal
section having a fine mesh for capturing thrombus, optionally a
proximal section having a coarse mesh adapted for crimping
attachment to the proximal arm, and an intermediate section having
apertures dimensioned to allow passage of thrombus into the
cage.
In another embodiment, the invention provides a device suitable for
use in a body lumen and comprising: an elongated control member
having a distal and a proximal end, and a cage disposed at or near
the distal end and adapted for collection and/or shearing of matter
from a wall of the body lumen, the cage having a proximal end and a
distal end and being adjustable between a contracted orientation
and an expanded orientation, the elongated control member
comprising a proximal arm connected to the radially expansible
member and a distal arm connected to the radially expansible member
distally of the proximal arm connection such that movement of one
arm relative to the other arm effects adjustment of the diameter or
radial strength of the radially expansible member, the device being
characterised in that the cage has an at least partially open
proximal end and tapers inwardly towards its distal end, and
wherein a helical extractor is optionally disposed within the cage
towards a distal end of the cage.
In one embodiment, the invention provides a device suitable for use
in a body lumen and comprising: an elongated control member having
a distal and a proximal end, and a cage disposed at or near the
distal end and adapted for collection and/or shearing of matter
from a wall of the body lumen, the cage having a proximal end and a
distal end and being adjustable between a contracted orientation
and an expanded orientation, the elongated control member
comprising a proximal arm connected to the radially expansible
member and a distal arm connected to the radially expansible member
distally of the proximal arm connection such that movement of one
arm relative to the other arm effects adjustment of the diameter or
radial strength of the radially expansible member, the device being
characterised in that the cage comprises a cutting or separation
element disposed circumferentially around the cage.
Preferably, the device of the invention comprises an extractor for
matter (i.e. debris such as thrombus) at least a part of which is
preferably disposed within the radially expansible member. The
extractor may comprise either aspiration, a helical formation
adapted to rotate and remove thrombus from the radially expansible
member, or a combination of both. The helical formation may
comprise a screw or auger, that is preferably arranged co-axially
about the second (distal) arm, but optionally may be arranged
eccentrically to the radially expansible member axis.
Alternatively, the helical formation may comprise a helical wire or
the like arranged, for example, around the distal arm and adapted
to rotate. Preferably, the helical formation is disposed within an
extractor tube, wherein a distal end of the helical formation that
is disposed within the cage is exposed proud of the extractor tube
(i.e. the tube may be cut-away leaving a part of the helical
formation within the radially expansible member exposed. In one
embodiment of the invention, the extractor comprises a wire
arranged helically about the distal arm for rotation about the arm,
and an extractor tube, wherein the helical wire and distal arm are
disposed within the extractor tube with a portion of the distal end
of the helical wire exposed proud of the extractor tube. Suitably,
the extractor tube comprises a window disposed within the cage,
typically disposed towards the distal end of the cage. Preferably,
a leading edge of the extractor tube comprises a sharp or cutting
edge.
In the device of the invention, the proximal arm is generally
connected at or adjacent to the proximal end of the radially
expansible member. Typically, the distal arm is generally connected
at or adjacent to the distal end of the radially expansible
member.
Preferably, the device is a thrombectomy device, ideally a
thrombectomy catheter.
The invention also relates to a method for removing matter from a
target area of a wall of a body lumen, for example thrombus from a
wall of a vein or artery, comprising a step of providing a device
according to the invention with the radially expansible member is a
contracted orientation, inserting the device into the target lumen
such that the radially expansible member is positioned distally of
the target area of the wall, adjusting the radially expansible
member from a contracted orientation to an expanded (deployed)
orientation, and withdrawing the radially expansible member along
the lumen such that the radially expansible member scrapes some/all
matter from the target area of the wall of the lumen.
The invention also provides a method of removing thrombus from a
blood vessel comprising the steps of placing the device of the
invention in a blood vessel, and moving the device along the blood
vessel. Typically, the device is moved along the blood vessel in an
inwardly tapering direction or an outwardly tapering direction.
Suitably, the blood vessel is a vein, typically a large vein.
BRIEF DESCRIPTION OF THE FIGURES
The invention will be more clearly understood from the following
description of some embodiments thereof, given by way of example
only, in which:
FIG. 1. Shows a braided cage in its expanded configuration, with a
filtered end (201) and an open end (202).
FIG. 2. An example of a cage made from laser cut Nitinol. The
distal side is solid tube and the proximal side is a closed mesh to
fit over the proximal arm tube.
FIG. 3. An example of a laser cut cage after expansion. The
circumferential elements act as filter and separate the thrombus
from the vessel wall.
FIG. 4. Cage with cutting element external to the cage.
FIG. 5. Cage with cutting element internal to the cage.
FIG. 6. Cage with cutting element as part of the cage.
FIG. 7. The perimeter of the cage may be tapered at an angle.
FIGS. 8A and 8B. Schematic of the cage and control mechanism,
operated using a friction screw.
FIG. 9. Schematic of the cage and control mechanism, operated using
a friction screw.
FIG. 10. Schematic of the cage and control mechanism, operated
using a friction screw and a spring.
FIGS. 11A and 11B. Schematic of the cage and control mechanism,
operated using a spring, and a movable stop.
FIG. 12. Schematic of the cage and control mechanism, operated
using a flat spring.
FIG. 13. Schematic of the cage and control mechanism, operated
using a flat spring.
FIG. 14. Schematic of the control mechanism, operated using a flat
spring.
FIG. 15. The extractor is made of a wire wrapped around a tube. It
transports and macerates the thrombus.
FIG. 16. The wire may be displaced above the tube surface.
FIG. 17. The proximal arm may act as the outer tube of the
extraction mechanism and provide a passage way to let material from
the blood vessel into the lumen of the macerator.
FIGS. 18A and 18B. The proximal arm of extractor with cutting edge
and larger extraction path.
FIGS. 19A and 19B. The proximal arm of extractor may have more than
one leading edge.
FIG. 20. Image of the macerator with a rotating tip/cutting edge.
The tip rotates with the helical formation.
FIG. 21. Shows the cage in its open configuration. The passageway
provided by the proximal arm, may be located inside the cage.
FIG. 22. The extractor may be eccentric to the centreline of the
cage.
FIG. 23. The tip of the extractor may be eccentric and positioned
away from the centreline of the cage.
FIG. 24. Section view--the extractor may contain a region with a
shorter pitch. This may compress the debris being extracted and
allow fluid to flow back through the cavities and into the
vessel.
FIG. 25. Section view--Combination of the cage and the extractor.
The cage is opened and closed by the relative movement of the
proximal and distal arms. The rotating extractor rotates over the
distal arm and within the proximal arm. A sheath can run over the
device to ensure the cage is closed during delivery and
retrieval.
FIG. 26. Section view--The distal end of the device showing an
embodiment of the cage with the extractor tube acting also as the
distal arm. As the distal arm moves proximally, the cage opens. As
the distal arm moves distally, the cage closes.
FIG. 27. Section view--The tip of the device. In this embodiment
the extractor tube also acts at the distal arm. The extractor tube
rotates at high speed while cage connector does not rotate. The
bearing facilitates this relative movement.
FIG. 28. Schematic of a device of the invention with a control
mechanism located within the cage.
FIG. 29. Schematic of a device of the invention with a control
mechanism located distally of the cage.
FIG. 30. Schematic of the device having a sheath covering the
elongated control member and adjustable to cover the cage.
FIG. 31. Schematic of the device of the invention showing how
thrombolytic agents may be infused through the extractor.
FIG. 32. Schematic of the device of the invention showing how
thrombolytic agents may be infused between the extractor and the
sheath
FIG. 33. Schematic of the device of the invention showing how
thrombolytic agents may be infused through holes or perforations
formed in the sheath.
FIG. 34. Schematic of a radially expansible member formed from a
single strut.
FIGS. 35A and 35B. Schematic of a radially expansible member formed
from two struts.
FIG. 36. An example of the radially expansible member made from a
series of wires, and fused or twisted for connection (shown as a
flat pattern).
FIG. 37. An example of a braided expansible member with the wires
twisted at the intersections to limit the movement of the wires
with respect to each other (shown as a flat pattern).
FIG. 38. An example of a braid configuration for the creation of a
braided radially expansible member, with twisted wires (for struts)
and fused ends (shown as a flat pattern).
FIG. 39. An example of a braid configuration for the creation of a
braided radially expansible member, with twisted wires to create
struts.
DETAILED DESCRIPTION OF THE INVENTION
Cage and Filter
The cage can be made in many different ways, such as from a braid,
a series of wires, laser cut tubes or a combination of them. The
cage also may act as a filter or be a structure for the filter at
the distal part. The cage can be made of different materials such
as, but not limited to, polymeric, metal such as stainless steel
Nitinol or cobalt chromium, or ceramic; or a combination of these
materials. The proximal side of the cage is generally open and
allows thrombus into the cage. The distal part of the cage is
suitably constrained onto a tube or wire with small diameter and
the proximal part of the cage is connected to a tube with larger
diameter. A sheath may cover the entire device at delivery and at
retrieval.
A connector, which can be a wire or tube and connects the distal
end of the cage to user or controls the distal movement of the
cage, is called the distal arm. Another connector, which can be a
wire or tube and connects the proximal end of the cage to user, is
called the proximal arm.
Once the cage is assembled and opened, section 202 provides a
passageway for thrombus into the cage, while section 201 prevents
large thrombus passing the cage (1).
In FIGS. 2 and 3, an example of a cage which has been laser cut
from Nitinol tube is shown. The laser cuts have the same feature as
the braided mesh. It provides a passageway on the proximal side and
acts as filter on the distal side. It may also carry
circumferential elements for cutting through thrombus and
separating thrombus from the wall.
By pushing the proximal and distal ends of the cage axially towards
each other the diameter of the cage and its radial force may
increase. By pulling the sides away from each other the diameter
and the radial force of the cage may decrease.
Relative movement of the distal and proximal arms controls the
distance between the distal and proximal sides of the cage; this
adjusts the diameter and radial strength of the cage. If the distal
arm is fixed and the proximal arm is pulled proximally by the user,
the diameter of the cage becomes smaller. If the proximal arm is
fixed and the distal arm is being pulled, the diameter of the cage
increases.
The cage may also have a circumferential cutting element for
removing/scraping thrombus from the vessel wall. This may be
contained around or within the cage and may be composed of a round
wire, flat wire, blade or a combination of these. FIG. 4 shows the
cage with a flat wire attached the outside of the cage; the wire
can scrape thrombus from the vessel wall. FIG. 5 shows the cutting
element internal to the cage, while FIG. 6 shows the cutting
element of the cage as one part (in this case from a laser cut
tube). The cutting/scraping element may also be tapered at an angle
(FIG. 7).
A Cage with Self Adjustable Diameter Control Mechanism
In the case of treating a tapered vessel, the cage diameter should
be adjustable while it is pulled along the lumen. Also in the case
of obstruction such as vascular valve it is desirable that the
device be able to manoeuvre through it. Therefore a mechanism which
can control the diameter of the cage by changing the resistance
force is desirable. Presented here is a mechanism to control the
diameter of the cage based on resistance forces.
As the cage moves through a reducing tapered vessel (pulling the
proximal arm), the vessel exerts a force on the cage. When the
force from the vessel exceeds the total force including the preset
force from the resistance mechanism (set by the user), the distal
arm moves distally relative to the proximal arm; this closes the
cage. The next section includes some embodiments of the
self-adjustment mechanisms.
The control mechanism may contain friction elements, springs,
pneumatics, hydraulics, simple weight, or a combination of these
elements.
Resistance Mechanism: Sliding
In this embodiment of the invention (FIGS. 8A, 8B, and 9), the cage
(3) is made from a laser cut self-expanding tube. The cage opens
when 1b and 2b move closer together, and closes when 1b and 2b move
apart. The mechanism for controlling the diameter and force exerted
by the cage on the vessel wall is the basis for the current
invention.
The device, as shown in FIGS. 8A and 8B, consists of a cage (3)
which has a distal end (1b) and a proximal end (2b), a distal arm
(1), a proximal arm (2), and a handle. The control mechanism is
comprised in the handle, and comprises a first part in the form of
a housing (2a) having a guidance path, a second part in the form of
a sliding block (1a) configured for sliding movement along the
guidance path of the housing (2a). Force controlled resistance
means is provided in the form of a brake adapted to resist movement
of one or the arms relative to the other. In this embodiment, the
brake comprises a friction screw (4) mounted on the housing (2a)
and adjustable to apply a compression force against the sliding
block (1a) to provide resistance to movement of one arm relative to
the other, and in the case of the device being passed along a
vessel that tapers inwardly, resistance to the compression of the
cage which has the effect of keeping the periphery of the cage in
contact with the vessel wall.
The process begins in an expanded state in the vessel as shown in
FIG. 8A. The opening and closing of the cage is governed by the
relative movement of the sliding block (1a) to the handle (2a). As
the cage is pulled by the handle through an obstruction or the
tapered section of the vessel (5), force from the vessel wall is
exerted to the cage. This force is transferred to the sliding block
(1a). If the force applied to the block 1a is larger than the
preset friction force, then the block 1a slides forward from its
position in FIG. 8A to its position in FIG. 8B. This allows the
cage to conform to the shape of the narrower vessel. The force
exerted by the cage on the vessel is therefore dictated in part by
the ease of movement of the sliding block relative to the handle;
this is controlled by the friction screw.
Resistance Mechanism: Sliding and Spring
FIGS. 11A and 11B show an alternative embodiment of the resistance
mechanism in which parts described with reference to FIG. 10 are
assigned the same reference numerals. In this embodiment, a
compression spring (6) is disposed along the guide path between the
housing (2a) and the sliding block (1a). The housing (2a) is
connected to the proximal arm (2) and the block (1a) is connected
to the distal arm (1). Thus, compression of the cage (3) into a
contracted orientation causes the distal arm (1) to extend, causing
compression of the spring. In this manner, the cage is biased into
an expanded orientation when it is being passed along a vessel that
is narrowing, thereby maintaining contact between the cage and the
vessel wall. A friction screw (4) is mounted on the housing (2a)
and is adjustable to apply a compression force against the block
(1a) and thereby provides further resistance to movement of one arm
relative to the other, and in the case of the device being passed
along a vessel that tapers inwardly, again provides resistance to
the compression of the cage which has the effect of keeping the
periphery of the cage in contact with the vessel wall.
FIGS. 11A and 11B show an alternative embodiment of the resistance
mechanism in which parts described with reference to FIGS. 8 to 10
are assigned the same reference numerals. In this embodiment, the
self adjusting mechanism comprises a movable stop (7) that is
movable to adjust the length of the guidance path and, thus, the
degree of compression of the spring. Thus, the force that the
spring applies can be varied by changing the position of the
movable stop (7) along the guidance path.
Resistance Mechanism: Spring with Adjustable Spring Constant
In this embodiment the distal arm (1) is attached to a flat spring
(22). The other side of the spring (22) is fixed respect to
proximal arm (2) through a solid handle (20). Since the spring
constant of a flat spring changes with its length, a mechanism for
adjusting its length (21) can slide over the spring to control its
deformation. When the sliding part (21) is down (FIG. 12) the
spring constant is the lowest which means it allows higher
displacement of inner tube (1) at a lower force. When the sliding
tube (21) rises (FIG. 13), the spring constant (22) increases which
allows less displacement of inner tube (1). This effectively
reduces the cage diameter (3). FIG. 14 shows a 3D representation of
the mechanism.
The Extraction Mechanism
The extraction system may consist of suction, or a rotating
tube/wire with a means of transformation and/or maceration on the
outer surface; the extraction system may also contain a combination
of these mechanisms. The rotating extractor may be manufactured
from one part or made from several attachments. For example, the
extraction mechanism may comprise a wire (42) wrapped around an
extraction core tube (43) (FIG. 15). This tube may be placed over
the distal arm (1) of the cage and inside the proximal arm (2).
Alternatively, the distal arm may be used as the extraction core
tube. The distal side of the extraction core tube may be close to
the distal end of the proximal arm (2). As the extraction tube
turns at high speed thrombus is forced proximally between the
extraction tube and the proximal arm. The distal end of the
extraction mechanism may be located inside the cage (FIG. 1).
The wire may have varying cross sections along the device for
different means; from circular, rectangular or triangular cross
sections. The wire can be from different materials such as
stainless steel, Nitinol, or polymers. Once the wire is wrapped
around the tube, it might be completely fit around the tube (41) or
be partially fit at a distance (43) from the rotating tube (41)
surface (FIG. 16).
The proximal arm may also contain a side window (FIG. 17) to
improve access of the extractor to thrombus. The extractor may also
be formed from one machined part rather than a wire wrapped around
a tube. The rotating extractor will likely contain sharp cutting
edges at its distal end to break up matter prior to extracting it.
The non-rotating proximal arm may also have a leading edge/cutting
element (FIGS. 18A and 18B) which helps to break down thrombus,
while also increasing the size of the path at the entrance of the
extractor. The proximal arm may have more than one leading
edge/cutting element to break down matter; FIGS. 19A, and 19B show
the proximal arm with two leading edges. The leading edge/cutting
element may form part of the proximal arm (as shown) or
alternatively be a separate part attached to the non-rotating
proximal arm. The extractor may also contain an additional port at
the proximal end where suction can be added to enhance thrombus
extraction, and to attract thrombus towards the extractor. FIG. 20
shows an embodiment in which the rotating tip and helical wire are
attached to the distal arm for rotation therewith. FIG. 21 shows
the extractor with the cage. The extractor may also be eccentric to
the centre of the cage; FIG. 22 shows the extractor eccentric to
the centre cage and adjacent to it while FIG. 23 shows the tip of
the cage away from the centre of the cage. In both FIGS. 22 and 23
the extractor may be stationary or rotate around the
centreline.
The extractor may have a varied pitch along its length. One
embodiment of this is shown in FIG. 24, where a section of the
extractor has a reduced pitch, and the non-rotating tube has a
number of small holes (acting as a filter) in it. This may allow
any debris to be squeezed, forcing residual fluid through the holes
and into the vessel while the remaining debris continues to be
extracted.
The extraction mechanism in combination with the cage may have
various functions along the device. In one embodiment, the
extractor breaks down the thrombi into relatively big pieces which
are small enough to enter the inlet of tube and big enough not to
pass through the filter. Once the thrombus is inside the tube, the
extractor, breaks them down into smaller pieces, make it easier to
transfer along the catheter. Then, the extraction system may have a
means of extraction such as helical wire or vacuum. The matter
removed will be collected in a suitable collection means, for
example a blood bag, or syringe or similar.
The helical formation may have a cutting edge, and which is adapted
to rotate with the helical formation and cut or break up thrombus
for extraction. The cutting edge may be a blade ore the like, and
may be disposed at or close to an end of the helical formation. The
extractor tube may also have a cutting edge, and may be adapted to
rotate.
Combination of the Cage and Extractor
The device contains both a cage with a self adjustment mechanism,
and an extractor. FIG. 25 shows an embodiment of the distal end of
the device. The device is opened and closed by the relative
movement of the proximal and distal arms, while the extractor
rotates over the distal arm and within the proximal arm. The
proximal arm may also contain a window for extraction. A sheath
covers the entire device during delivery and retrieval.
FIG. 26 shows another embodiment of the distal end of the device,
with the cage and extractor combined. In this embodiment, the
rotating extractor also acts at the distal arm; the relative
movement of which opens and closes the cage. A ball bearing has
been included to facilitate contact of the rotating
extractor/distal arm and non-rotating proximal arm and cage (FIG.
27).
Device with Control Mechanism within Cage
FIG. 28 shows an embodiment of the device in which the control
mechanism is disposed within the cage. In this embodiment, a
control mechanism is provided within the cage (3) and comprises a
first part operably connected to the proximal arm (2), a second
part operably connected to the distal arm (1), and a helical spring
(6) connecting the first and second parts. In use, as the cage
passes along a vessel that is tapering inwardly, the control
mechanism ensures that a force controlled resistance is applied to
the cage as it contracts, thereby ensuring that the cage remains in
contact with the walls of the vessel.
Device with Control Mechanism Mounted Distally of Cage
FIG. 29 shows an embodiment of the device in which the control
mechanism is disposed distally of the cage. In this embodiment, the
device comprises a proximal arm (2), which is connected to a
proximal part (2b) of the cage and which extends through, and
distally beyond, the cage, and a distal arm (1) which extends
distally of the cage (3). The control mechanism comprises a first
part (block 1b) operably connected to an end of the proximal arm, a
second part operably connected to the distal arm (1), and a helical
spring (6). In use, as the cage passes along a vessel that is
tapering inwardly, the control mechanism ensures that a force
controlled resistance is applied to the cage as it contracts,
thereby ensuring that the cage remains in contact with the walls of
the vessel.
Device with Outer Sheath
Specifically, FIG. 30 shows an embodiment of the device of the
invention in which a sheath (8) is provided that covers the
elongated control member. In this embodiment, the device can be
manipulated such that the cage (3) is contracted and withdrawn
within the sheath, which will thus keep it in a contracted
orientation
Delivery of Liquid Agent to Vessel Lumen
The device of the invention may also be employed to deliver liquid
agent, for example a thrombolytic agent which can break down
thrombus, to the vessel lumen. This may be achieved in a number of
different ways including: The direction of rotation of the
extractor screw can be changed to infuse rather than extract.
Inject through the hollow distal arm. Inject through a lumen
between the distal arm and the extractor tube (proximal arm) (FIG.
31) Injected in between the extractor tube (proximal arm) and the
sheath (FIG. 32). Injected through cavities in the sheath (FIG.
33). The location of the sheath and cavities can be adjusted along
the catheter length. One of, or a combination of, the above methods
of infusion.
Generally, the liquid agent would be injected into the delivery
lumen, which may be any of the above. Alternatively, the liquid
agent may be delivered slowly by means of a drip feed. As indicated
above, the liquid agent may be delivered in a number of different
ways, for example through a hollow distal arm (which has the
advantage of being capable of delivering liquid agent distally of
the cage), through a lumen formed between the distal arm and the
proximal arm (also referred to as the extractor tube), or through a
lumen formed between the proximal arm and the outer sheath.
Design of Radially Expansible Member
FIGS. 34 to 39 describe embodiments of the radially expansible
member forming part of the device of the invention, and
specifically braid configurations that may be employed in radially
expansible members.
The invention is not limited to the embodiments hereinbefore
described which may be varied in construction and detail without
departing from the spirit of the invention.
* * * * *